Telescopic antenna



Nov. 15, 1949 MfsPlRT 2,488,480

TELESCOPIC ANTENNA Filed Feb. 18, 1946 2 sheets-sheet 1 f 1M EN TOR.

TTOF/V'y Nov. 15, 1949 M. sPlRT TELEscoPIc ANTENNA 2 Sheets-Sheet 2 Filed Feb. 18, 1946 NVENTOR. BY m y m Patented Nov. 15, 1949 UNITED STATES PATENT OFFICE 1 claim. 1

The invention here disclosed relates to collapsible antennas.

These devices usually consist of a set oi telescopically engaged tubular sections which can be extended or collapsed at will.

Particular objects of the present invention are to provide simple and effective means for retaining the sections in their assembled relation and for applying a desired tension for holding the sections in their Various positions of relative adjustment.

Special objects also are to provide uniform tensioning and retaining means which will be light and inexpensive and capable of being quickly and easily applied in the operation of assembling the several parts.

Other desirable objects and the novel features by which the purposes of the invention are attained are set forth or will appear in the course of the following specification.

The drawing accompanying and forming part of the specication illustrates a present preferred embodiment of the invention. Structure, however, may be modif-led and changed as regards the immediate illustration, all within the true intent and broad scope of the invention as hereinafter dened and claimed.

Fig. 1 in the drawing is a broken side elevation of a collapsible antenna equipped with the invention;

Fig. 2 is an enlarged broken sectional view of the same showing the parts in collapsed relation;

Fig. 3 is a similar View showing the sections extended;

Fig. 4 is a broken sectional detail as on substantially the plane of line 4 4 of Fig. 3;

Fig. 5 is a detached detail view of the retainer and tensioning spring.

Figs. 6 and 7 are broken longitudinal sectional views of a modiiication; and

Fig. 8 a cross section on line 8-3 of Fig. 6.

Fig. 1 is an external View of a three-section collapsible antenna made up of a tubular base section l, a tubular intermediate or second section 8 and a rod or end section 9.

riihese three sections are slidingly guided and confined, one within the other, by forming the tubular sections with reduced upper ends l0 and H snugly ntting the members 8 and 9 sliding within the same. rhe reduced ends, in addition to forming guides, provide internal shoulders to serve as stops for preventing separation of the parts.

The rod section 9 is shown as having a swaged portion l to act as a stop engageable with the internal shoulder at the reduced neck portion Il and the external inner end of the rod is shown bent at i3 to tension it against the inner wall of the tube The middle section is spring tensioned and held against separation from the base section by a special retainer shown in the form of a spring wire clip doubled into U-shape with a substantially circular bow lli and side arms l5 indented from the bow at it and having at their ends outwardly bowed portions Il and inwardly directed straight terminals IS.

This retainer clip, in the first form of the invention illustrated in Figs. 2, 3 and 4, is engaged with and attached to the section 8 by slipping it into the lower end of that section until the outwardly bowed end portions Il spring through oppositely located side slots i9 and the bowed head portion l enters a cross slot 2li in the end of the tube.

This assembly is effected before the closure plug 2l is applied to the end of the base section 'l and hence while the open end of the intermediate section is fully accessible.

After the clip has been engaged as described in the end of the intermediate tube, the split end portions of the tube are bent together against opposite sides of the circular head of the clip so as to center and hold it in place, as indicated at 22 in Fig. 4.

As shown in Fig. 5, the spring wire clip is formed with the arms spread apart, so that it must be pinched together to enter it in the end of the tube. In nal position the arms are spring tensioned apart, with the rounded elbows Il' projecting freely outwardly through slots I9 into spring tensioned frictional engagement with the inner wall of the base tube l. In this closed or partially closed position of the clip the rounded head portion iii is of a diameter preferably to approximately nt the interior of the surrounding tube to serve also as a guide and spring tensioning element.

The outwardly bowed portions I1 at the ends of the spring arms are abruptly angled sufficiently to act as stops when engaged with the internal shoulder 23, Fig. 3, to limit the withdrawal movement and positively prevent the intermediate section 8 from being drawn out of the base section 1. The straight end portions I9 are shown as of a length, to abut, in the assembled relation of the parts, Fig. 3, to prevent collapsing of the spring such as would permit of the tube being withdrawn from the base section.

In the normal active position of the clip shown in Figs. 2 and 3, the spring arms I5 are held collapsed, in generally parallel relation, free of engagement with the interior of tube 3 so that the full spring force of the clip will be eective at the rounded shoulders I1 in sliding engagement with the inner wall of the containing tube.

The clip can be quickly and easily inserted in the end of tubular section 8, while that section is still accessible at the open end of the base section 1, and when so engaged it becomes a stop which by cooperation with the internal shoulder 23 will prevent separation of the tubular sections and a tensioning device which will hold the parts against any looseness or rattle and which will smoothly and uniformly tension the movement of the one tube section in the 'other and yieldingly retain the shiftable tube section in the collapsed or in any adjusted position of the antenna.

While a three-section antenna has been illustrated, it will be appreciated that the invention may be applied to antennas of greater or less numbers of sections.

In the form of the invention illustrated in Figs. 6, 7 and 8 the spring clip is secured in the movable tube section by simply indenting the tube at 24 at opposite sides of the slots I9 to guide and conne the projecting shoulder portions I'l. This construction holds the spring clip firmly in place wit-hout need to engage the end of the clip in a slot in the end of the tube, as in the first embodiment illustrated.

Fig. 6 shows how the abutting ends of the clip may act as a stop engageable by the inner end of the rod 9 to limit the inward movement of the rod in its tubular support.

What is claimed is:

The collapsible antenna here disclosed, com- 4 prising telescopically related, outer and inner tubular sections, the outer section having a contracted upper end portion providing an internal annular shoulder, the inner section having slots in opposite sides near the lower end of the same and a spring clip of generally U .form disposed within the lower end portion of said inner tubular section and having outwardly bent end portions projecting outwardly through said side slots into sliding, spring tensioned frictional engagement with the inner wall of the louter tube below said abutment shoulder and thereby arranged to engage said internal annular shoulder of the outer tubular section to prevent withdrawal of the inner tubular section from said outer tubular section and the extreme ends of said outwardly bent end portions being disposed opposite each other Aand substantially in abutment when the parts are assembled as described to prevent collapsing movement of said end portions such as would free the same from abutting engagement with said internal shoulder of the outer tubular section. v A 1 MILTON SPIRT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,646,049 Boye Oct. 19, 1927 2,170,684 'Greenberg Aug. 22, 1939 2,179,415 Mace Nov. 7, 1939 2,217,188 Snyder Oct. 8, 1940 2,265,794 Aske Dec. 9, 1941 2,391,202 Tellander Dec. 8, 1945 2,443,294 Bickle l June 15, 1948 

